Hello-

I have an '04 F150 FX4 with two issues that I wondered if anyone else had noticed:
1). When going over road bumps, the truck wants to shudder on the rebound after the bump, and this fells almost like a 'tuning fork' resonance. The harder the bump, the longer the truck shakes or resonates. Could this be from the LT 18" Goodyears , or is something else amiss . It doesn't matter what wheel goes over the bumps either, but the whole cab sets up with a secondary resonance or shudder. Wonderef if anyone else noticed this?

2). Also, still have the problem from a dead start of getting a drive line type shudder every time (similar to going over a light speedbump) when starting out until truck gets to about 5-10 mph, then disappears.The local dealer mechanic said they had a problem last year with the E-150 vans, and it was the pinion angle off, but could not verify this as the issue on the '04 . The factory rep took the truck out, and acknowledged this; he even tried another one out that did the same , but was less pronounced.( It will not do it in reverse.) He said to live with it at this time with no answer to a fix! I then tried out another truck on the lot, and it didn't do this. Anyone else out there with this problem? I can't believe Ford's response, considering what is at stake with these new trucks.

 

Edited

 

I road tested a supercrew Lariat w/ "P" tires on it a few weeks ago and while driving down the most bumpy road I could find I did not notice any thing that I would consider a shudder. Now that I have purchased my supercrew w/ the "LT" tires I have occasionally felt a small shudder, nothing serious. I was thinking maybe the shocks where just a little too stiff in combination with harder tires.

 

yeah, i noticed a slight shudder on my Lariat 4x4 with LTs. I don't think it's a big deal. it is a little bumpy on the highway at 75mph, but that is to be expected i think. when i go over speed bumps, no problem. the shudder is just off the line for me. i don't know much about he limited slip, but i think that might be it doing its job, i mean, you chouldn't chirp the tires on my stock truck no matter how hard you tried (and believe me, i tried). i don't think it's a big deal.

my question is, is there a new car EXTERIOR smell? I mean, do the brakes or something else smell funny for on a new truck? my truck smelled funny when I brought it home last night, not sure what it is.

 

Don't know about the shudder. However, I do know limited slip. When traveling off the line without turning the limited slip should even be kicking in unless you are attempting to spin the wheels. It will work to attempt to spin both rear tires.

DO NOT USE A FRICTION MODIFIER with a limited slip rearend. The limited slip uses clutches on each of the axles to cause the other axle to function. It transfers power from the wheel that is slipping to the wheel that is gripping. Anyway, if you use a friction modifier you can mess up the clutches and the limited slip won't work.

If it is the limited slip it is a clearance issue in the rear end and normal break in should fix the problem.

 

Mine was that way for the first day or so. I chalked it up to some kind of leftover residue from the manufacturing processs getting burned off.

 

No, Dave, you're not alone (or crazy!). I had a '99 that had the "shutters". On takeoff, unless I rolled on the throttle slowly, it would happen. I never got to the bottom of it, but my guess was that it was coming from the differential. It felt as though the entire housing was twisting up and down slightly. Perhaps a combo of pinion angle, spring rate, tire sidewall stiffness, etc. was contributing to a twisting on launch. Torque converters also can do some strange stuff when not hooking up properly. Who really knows?

 

I seem to have the same thing with my truck on take off. Not sure what it is but only had it for 2 days and I'm hoping that it will fix itself within the breakin period. I know what you mean about the smell, the first night I got home I parked it in the garage and now the whole house smells like a new truck.

 

this sounds like something that adding a traction bar would fix. anyone agree or disagree with me?

 

I am not sure about the 04's but 03's and below with limited slip MUST USE friction modifier or you will have problems. I would check with Ford before anyone with limited slip decides to go without the friction modifier. That could void your warranty...